* WIP
* Convert Ethcore error to use error_chain
* Use error_chain for ImportError and BlockImportError
* Fix error pattern matches for error_chain in miner
* Implement explicit From for AccountsError
* Fix pattern matches for ErrorKinds
* Handle ethcore error_chain in light client
* Explicitly define Result type to avoid shadowing
* Fix remaining Error pattern matches
* Fix tab space formatting
* Helps if the tests compile
* Fix error chain matching after merge